1. Field of the Invention
This invention relates generally to the hydraulic shock absorber art, and more particularly to an improved heavy duty hydraulic shock absorber which is adapted for various uses, as for example, industrial machines, as in molding machine transfer equipment, overhead crane stops, and other similar applications, and which is capable of being adjusted to provide controlled, linear deceleration of loads.
2. Description of the Prior Art
The prior art hydraulic shock absorbers generally include an inner pressure chamber which is filled with fluid, and in which is slidably mounted a piston that is connected to a piston rod which is adapted to receive impact forces. The pressure tube of the prior art shock absorbers is provided with metering orifices through which fluid is forced when the piston rod receives an impact load. The prior art shock absorbers are provided with means for regulating the opening of the metering orifices. However, such prior art constructions have the disadvantage in that they are not as efficient as might be desired, and there is leakage or slippage between the inner pressure tube and the means for regulating the opening of the metering orifices. Another disadvantage of the prior art hydraulic shock absorbers is that the means for adjusting the opening of the metering orifice does not provide a fine adjustment means, nor does it provide a sharp edge means for controlling the opening of the orifice. A further disadvantage is that the prior art shock absorbers are not capable of providing heavy duty controlled reduction of impact forces with a fine adjustment over a wide range of impact forces and with a self-contained construction.